Air circulating mechanical refrigerator



Dec. 24, 1940.

L. C. MONTGOMERY AIR CIRCULATING MECHANICAL REFRIGERATOR Filed Nov. 4, 1956 3 Sheets-Sheet 1 Ylf'llfllllllliillll'llLP.

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3 Sheets- L. C. MONTGOMERY AIR CIRCULATING MECHANICAL REFRIGERATOR Filed NOV. 4, 1936 Dec. 24, 1940- llll'llll |l..| |||\|l|l 1 1 1 1 1 1 1 1 /1 1 9 1 11 1 1/ 1/ 11 111/1. /1 1 1 I Dec. 1940- c. MONTGOMERY 25,706

AIR C-IRCULATING MECHANICAL REFRIGERATOR Filed Nov. 4, 1956 s Sheets-Sheet s Gil Patented Dec. 24, 1940 Ala cracunarmc uscnamcsr.

aerarceas'ron Lonnie (1. Montgomery, Whittier, Calif. Application November 4, 1936, Serial No. 109,0a9

3Claims.

My invention pertains to so-called mechanical refrigerators in which by some type of refrigerating equipment refrigerator units are utilized located in a sense in separate compartments. These compartments are however provided with means for air circulation between the two compartments.

There are certain disadvantages in mechanical refrigeration, especially as applied to domestic or small sized refrigerators, among which may be mentioned the frosting, that is, freezing of moisture on the cooling coils. As ice itself is a relatively good heat insulator, the eflieiency of the heat transfer between the air of the compartment of the refrigeratorto the refrigerating liquid in the coils is decreased. It is therefore necessary to remove this ice from the cooling coil periodically. This is termed "dc-frosting.

Also, in the mechanical refrigerator during the defrosting'operation and the time consumed for this, the refrigerator is allowed to become warm, usually either by stopping the refrigerating unit or by decreasing the refrigerating action so that.

the exterior of the cooling coil may rise above the freezing point. This allows all of the interior of the refrigerator to become warmed to a temperature considerably above that which is desirable for maintaining the produce or commodities in the refrigerator at a desired refrigerated temperature. Frequently this action causes the spoiling of produce in the refrigerator. Moreover the continuous chilling and warming oficertain produce is decidedly disadvantageous. In certain types of commodities this alone causes a spoiling and waste of food products.

Another disadvantage of the usual mechanical refrigeration is the extraction of moisture from vegetables and fruits due to the continuous circulation of the same airin the refrigerator, the drying of this air by freezing or condensing of the moisture on the cooling coil and hence the supply of this moisture to the dry air from the vegetables, fruits or similar commodities. In fact, in the usual mechanical refrigerator it is necessary to make special provision by having separate compartments to retard-the drying of vegetable products of various kinds. A further annoyance is developed by the odors of certain products being taken up by other produce in a mechanical refrigerator. This is due in part to the ddors being carried by the circulating air, especially by the moisture of the air which in partially condensing on other cool produce causes a transfer of the odor from for instance a product which is quite pronounced as to certain odors, to other products which practically lack a definite odor. Manifestly this is disagreeable. In the ordinary mechanical refrigerator in addition, it is necessary to make provision for a down and an up flow of air in the one refrigerator compartment due to (Cl. 8H)

-- the cooling action of the cooling coils which ordinarily are placed at the top of the refrigerator so that. the chilled air being denser than the warm air descends to the bottom of the refrigerator compartment and the warm air flows up. Sometimes there is a distinct intermingling of this direction of flow which prevents the chilled air reaching the bottommost part of the refrigerator chamber.

There are also certain disadvantages of ice re frigerators in that it is necessary to service these quite frequently in order to maintain a large body of ice in the ice compartment, for it is onlyfiby miantaining a sufliciently large quantity of ice that a uniform refrigerating temperature may be maintained in the commodity compartments of the ice refrigerator. The ice refrigerator has certain advantages however, in that the melting ice supplies moisture to the air which is continuously circulating in the commodity space and thus fruits, vegetables and the like are not dried out by extraction of moisture therefrom. In addition, the odors of certain. produce carried by the vaporof the air are removed from the refrigerator. This is probably due to the warm rising air when coming in contact with the block of ice having a part of its moisture condensed on the block and then this is carried away with the waste water from the melting ice. Due to this action of the water from the melted ice being carried by a drain pipe completely out of the refrigerator, there is no water standing for any material length of time in the refrigerator.

, An object and feature of my invention is to overcome many of the disadvantages of the socalled mechanical refrigeration and to incorporate a number of the advantages of the ice refrigeration system. To this end I make the refrigeration and de-frosting automatic and have'a definite path established for the circulation of the chilled and the warmed air. In a simple type of refrigerator such as would be suitable for domestic use, I use dual cooling units or cooling coils, these being separated by an insulated partition which partition however, has provision such as openings adjacent the bottom and top for the circulation of air between the two compartments of the refrigerator. The automatic control is such that while one cooling coil is operating for refrigeration, that is, it is cooled to a low temperature, the other coil is allowed to warm up for de-frosting. This develops an air circula tion downwardly in one compartment from the chilling coil, the cool air passing through the openings adjacent the bottom of the partition to the other .compartment in the refrigerator where such air is warmed by the produce contained therein and by transfer of heat from the exterior of the refrigerator so that the warm air in rising and having a direction of flow around the second cooling coil causes a warming of such coiland hence a de frosting. This uprlslng current of air passes through the openings adjacent the top of the partition to the first mentioned compartment.

Another object and feature of my invention is in the provision for automatically operating one coil as a refrigerating unit and having the other inactice by means of one or more control valves which are operated by one or more thermostats and such valves directing the flow of the refrigerating fluid from the compressor to one or other of the cooling coils located at the upper part of'its own compartment of the refrigerator. Provision is'made for an outflow of the water melted from the cooling coils so that this does not remain in the refrigerator.

An advantage of this construction and system of mechanical refrigeration is that at no time will 20 one of the compartments become warmed to a suflicient extent that it would be injurious to the produce contained therein. A positive circulation is developed of the cool air downwardly in one compartment and the warmed air upwardly in the other compartment. This prevents countercurrents of air in the same compartment. In addition, the produce in both compartments is kept from drying out due to maintenance of a proper moisture content in the cir- 30 oulating air in both com artments as manifestly when one cooling coil is being de-frosted,

35 are not transferred from one produce to another.

It is presumed that these odors are in some manner carried by the circulating air probably by the moisture or water content of the air in the upflowing stream of air in one compartment 40 in. which the cooling coil is being de-fnosted. If there is excessive moisture in the upflowing air a portion of this will be condensed on the cooling coil being de-frosted and flow out with the water melted from the ice. The vapors car- 45 ried over to the chilling coil of the first compartment are condensed with the excess moisture forming a. coating of ice on the coil which is actively engaged in the refrigerating and chilling. As an automatic switch-over is made in having for instance a first cooling coil operative for refrigeration and the other inoperative for de-frosting, no personal attention is required to this de-frosting action. Moreover, with this type of refrigerator as the bottom of both com- 55 partments is the coldest portion, the produce whichit is necessary to maintain at a lower temperature than other produce, may be placed in the bottom portions of the two compartments and such produce undergoes very little change 80 of rise and fall of temperature in the de-frosting period of the cooling coils.

a A further characteristic of my invention is that the thermostats for-controlling the switchover of the refrigerating units should be mount- 65 ed preferably contiguous to these units. As the valve for reversing the flow of the refrigerating fluid is influenced by the warm temperature at thecoil being de-frosted, this part of the refrigerator wouldjae the warmest portion thereof. It

70 will be understood that the thermostats may be of any suitable type and control the action of the refrigerating fluid valve in any suitable manner which arrangement may be an electrical control or a mechanical control or a combination '5 of both.

My invention does not necessitate particular improvements in the refrigerating appliances per se as most of the types now on the market can be readily adapted for the purpose of this invention and therefore I do not describe the 5 refrigerating equipment in detail except such as is necessary to indicate the reversal of flow of the refrigerating fluid.

My invention is illustrated in the accompanying drawings, in which: 1 l0 Fig. 1 is a. front elevation of a domestic type of mechanical refrigerator equipped with my invention.

Fig. 2 may be considered either a side elevation taken in the direction of the arrow 2 of Fig. 1, the side wall and certain interior parts broken away, or on the section line 2-2 of Fig.

3 taken in the direction of the arrows.

Fig. 3 is an elevation of the interior of the refrigerator with parts broken away and illustrating the refrigerating assembly in a more or less diagrammatic manner.

Fig. 4 is a diagram showing in part the dual refrigerating units or coils and a thermostat control for electro-magnetically controlling a valve forming a commimication between the refrigerator fluid compressor or body of compressed fluid and the two cooling imits.

Fig. 5 is a diagram showing a mechanical connection for operating the fluid valve.

In my invention I utilize a more or less conventional refrigerator cabinet II which is illustrated as having an upper part l2 with a space for a refrigerating machine which may be a compressor alone or with! a compressor condenser assembly of the conventional type. The lower part l3 also provides a space for a. condenser where this is separate from the assembly with the compressor. A door I4 forms an opening to the interior of the cabinet which has the usual heavy heat insulated walls designated [5. The refrigerator thus provides the usual food storage space having a, floor l6 and a series of trays i-l. Thetop wall I8 separates the cooling units and storage space for produce from the upper part [2 having the refrigerating machinesuch as the compressor and condenser.

In my invention I installa central partition 20 between the bottom l6 and thetop [8, this runnin from the back 2| of the storage compartment to the front 22 which is closed by the door l4. There is a lower air circulating opening 23 and an upper opening 24 adjacent the top l8 for the same purpose. These are shown as slots extending from the back to the front of the storage space for produce. By this-arrangement I provide two compartments 25 and 26 on each sideof the partition for the storage of produce and to separate the cooling units, that is, the evaporators 21 and 28. These evaporators may 0 be of the usual character and are generally formed of coils of pipe 29 through which the refrigerating fluid is caused to flow in any suitable manner.

In the construction illustrated in the drawings and diagrams acompressor unit 30 is illustrated located in the upper part [2. From this as shown in Fig- 3, a pipe 30' leads downwardly to a condenser unit 38 which is located in the lower part l3. A feed pipe 3| thus from 33 condenser of the compressor and the condenser assembly discharge through a conventional expansion valve 32 and thence' to a two-way shifting valve 33 from which there are feed pipes 34 and 35 leading to the evaporating 'lmits 21 and 28. 7

Each of these units has a flow pipe, 35 and 31,

for suction flow direct to the compressor, these being illustrated in Fig. 3 as connected through a T coupling.

With my invention I utilize two water pans and II, each located below the cooling unit in a compartment to receive the water from ice melted off the coils 29 of each unit. A waste water or drain pipe 42 connects to each pan, each pipe having a gooseneck 43 forming an air trap. The drain pipes may discharge completely out of the refrigerator cabinet, the waste water being led away in any suitable manner or if desired they could lead-to water receptacles M which may be emptied in a conventional manner when desired. A suitable manner for cutting the cooling units 21 and 28 in and out of refrigerating action is shown particularly in Fig. 4 in which the valve 35 for supplying the refrigerating fluid to either of the cooling units is provided with an operating arm secured to the stem or spindle 5| of the valve 33. This arm is connected by a tension spring 52 attached to one end 53 of the arm and at 54 to a fixed structure of the cabinet. The opposite end of the arm has a slotted yoke 55 in which operates a pin 56 on a transversely moving rod 51. This rod has end portions 58 and 59 which function as movable armatures for the electro-magnetic devices 55 and 5|, each of which has a suitable wire winding 62..

The thermostat control designated by the as- 4 sembly numeral 55 employs two thermostats 65 and 61, one of these being installed in one of the food compartments 25 and the other in the second food. compartment 26. For purposes of illustration, these are shown as the diaphragm type but may be of any suitable character. Each thermostat has a plunger or movable end 68 operating a switch lever 65 shown pivoted at 15. Each lever V The electric circuit is illustrated as having a lead 80 connected to a power source, this branching as indicated at 8| and having leads 82 and 83 connecting respectively to the switch arms 62 and thus to the moving contacts H. From the fixed contact 72 there are electric leads 84 and 85 to one end of each of the windings 62 of the electro-magnetic devices till, 5 I The opposite end of each coil has a connection 86 to its brush 15 and from such brush there is a return lead 8'! to ground 88. The source of current supply also has a ground connection.

In the operation of this type of device the overbalance spring 52 always maintains the valve 33 in one of its open positions, that is, communicating from the pipe 3| to one of the cooling units 21 or 28 but it can never form a connection to both of these. In the illustration of Fig. 4 it is presumed the connection is to the cooling unit 271 which thus. receives the refrigerating fluid to fluidtherethrough, this causes a chilling of the air in the left hand-compartment 25 (note Fig. 3) This of course cools the air immediately surrounding the cooling unlt 21 which becomesdenser than theair therebelow and develops a downward circulation of air as indicated by the arrows 95. This air flows through the lower opening 23 as indicated by the arrows 9| entering the warming compartment 26 adjacent the bottom. As the cooling unit 23 of the comparta mer t 26 1s out of action, that is, there is no coolifng fluid circulating therethrough, the coils of this unit have no chilling action except for the ice which may be on such coils, hence the air in the compartment 26 becomes warmed and develops an upward direction of flow indicated by the arrows 52. The temperature of this air rises the higher up it gets in the compartment 25 and thus a body of comparatively warm air is brought into contact with the cooling unit 28 and melts the ice formed on the coils 29 of such unit. This causes a ole-frosting action, the water dripping into' the pan 4| and flowing outwardly through the waste or drain pipe 42. The heated through, it is at a low temperature and hence as the warm air passing through the top opening 24 contains moisture, a proportion .of this is condensed on the )cooling unit 2'! depositing in the form of frost or ice. The moisture contact of the warm air has been supplied in part by the melting ice and frost on the cooling unit 28 which is undergoing de-fristing. Of course before this unit is completely de-frosted and is covered with ice, the vapors carried by the upwardly flowing air 92 will be to a certain extent condensed on the melting ice on the unit 28 and a further amount condensed on the unit it.

The circulation of air continues as shown by g the arrows 95, 9t, 52 and 93 until the thermostat 5'! in the food compartment 26 expands due to its increased temperature and closes its switch having the contacts H and 12. During this operation the rod 5'5 and the armatures 58 and 59 connected-thereto occupy a left hand position as shown in dotted lines in Fig. i. This is a position of rest in which the.valve armjtl could occupy a position reverse of that shown in Fig. 4. There is then an electrical contact between the conducting bar it and'the brush 15 which brush is associated with the electro-magnetic device Bl.-

Hence an electric circuit is established from the source of power through the leads 83, the

" switch contacts H and 12 on the right hand side,

the right hand leads and 85 to the winding 52 of the electro-magnetic device 5i, thence through the brush E5 on the right hand side to its contact bar it. This gives a momentary energizing of this electro-magnetic device 8! developing a movement of its armature 59 and hence of the whole rod 51 and the opposite armature 58 bringing these to the position shown in full lines in Fig. 4 which action breaks the circuit between H and the brush [5 on the right hand side thus tie-energizing the electro-magnetic coil The movement of the bar 51 from the left hand, that is, the dotted position of Fig. 4, to the right hand full line position of the same figure moves the valve arm 50 from the dotted to the full line position, thus turning the valve 33 to establish the flow of the refrigerating fluid from the pipe 3| to the cooling coil 28 flow to the cooling coil 21.

Thus the cooling unit 28 is brought into refrigerating action and causes a chilling of the air in the upper part of the compartment 26. This action slowly stops the circulation of air until it is cooled sufficiently to descend in this compartment 26 in a reverse direction to the arrows 92 and flow upwardly in the left hand compartment 25 reverse of the direction of the arrows 90. This action brings warm air into contact with the cooling unit 21 which in the prior action has become coated with ice or frost and it undergoes a de-frosting action and thus melts the ice in the unit 21, the water dropping into the pan 40. When the temperature in the compartment 25 rises to a predetermined value, the thermostat 61 expands and closes its contact switch. Of course manifestly as the compartment 26 cools, the thermostat 61 contracts and opens its switch. The cycle of operations is then repeated at periodical intervals, dependent on the rate of refrigand out off the eration of one compartment and the rate of heating of the other.

Presuming it is desired to start the refrigerator operating in which both of the chambers are warm, it is immaterial which cooling unit first comes into operation as the over-balance spring 52 will always hold the valve 33 in one of its extreme positions, that is, either feeding the refrigerating fluid to the cooling unit 21 or 28 but not to both at the same time. I

In Fig. 5 I illustrate a mechanical arrangement for operating the fluid valve for directing the flow of the refrigerating fluid to one or other of the cooling coils. In this case I show two diaphragm type of thermostats designated I and IOI, each of which has a plunger I02 connected to the diaphragm and operatively connected to one end of a lever I03 and I04 fulcrumed at I05 on a fixed structure. Flexible cables I06 and I0! lead from these levers passing over change of direction pulleys I08. Each cable has a spring I09 and H0 connected thereto and the springs being attached to a single link I I I, such link being pivotally connected to the actuating'arm II2 of the valve 33. An over balance spring H3 is connected at one end to a fixed structure and at the other end to the pivot I I4 connecting the arm I I2 to the link I I I.

The operation of this device is substantially as follows: Presuming the arm I I2 has been located in a position directing the refrigerating fluid through the pipes 3I and 34 to the refrigerating unit 21, this allows the thermostat IOI to become heated, giving a movement of the lever I04 from its tilted up position to a downwardly inclined position, thus exerting a tension on the cable I01 and through the spring H0 and the link III moving the arm II2 past the center so that the over balance spring II3 will give a quick action in finally shifting the valve. It will be understood that when the refrigerating unit 2.! is being cooled that the diaphragm in the thermostat I00 collapses or retracts, thus positioning the lever I03 in the position shown in Fig. 5 and slackening the cable I06 so that as soon as the cable I01 develops a tension there is no difiiculty in. actuating the arm of the valve. the valve is moved to the position shown in full lines in Fig. 5 the refrigerating fluid is directed through the pipes 3| and 35 to the refrigerating unit 28 causing this to become chilled. The thermostat IOI thus being in a cooling compartment retracts, easing the tension on the cable I0'I As soon as.

and the thermostat I00 in the compartment which is warming up expands and develops a tension on the cable I06. If for any reason on account of for instance the refrigerator door being open, both of the thermostats are heated and expanded, this would exert a tension on both cables I06 and I01 and on their springs I09 and I I0, but the over balance spring I I3 has sufiicient tension to always maintain the arm H2 in one or other of the open valve positions so that one refrigerating unit at a time is functioning.

Important characteristics of my refrigerator and method of refrigeration may be defined as follows, referring particularly to Fig. 3. In this case the refrigerating unit 21 is presumed to be operating, that is, actively refrigerating and thus cooling the air in the compartment 25. The air chilled by passing over and in close contact with the refrigerator unit 21 becomes denser and develops a downward flow in this first compartment 25. This causes a cooling of the-products in such compartment of the whole refrigerating space. It is, well known that many of the articles of food kept in a refrigerator give oflz various odors and other products absorb such odors giving a disagreeable combination of tastes to various foods. These odors are carried by the moving air in the refrigerator and to a certain extent by the vapor or water content of such air. The refrigerating unit which is in operation tends to freeze the moisture out of the air passing over such unit and thus condenses the moisture in the form of frost on the active cooling unit. This incidentally to a certain extent, dries the air.

While the refrigerant is passing through the cooling unit 27 and thus is actively engaging in refrigerating operation, the flow of refrigerant through the other unit 28 is stopped. Therefore this unit is inactive. Hence it has no active refrigerating function in the second chamber 26 separated from the first by the partition 20 which has the opening 23 at the bottom and the openings 24 at the top. Therefore the air in the compartment 26 becomes warmed. Also there is a positive downward circulation in the compartment 25 which combined with the heating of the air in the compartment 26 produces the upward flow of air in this second compartment. The downward and upward direction of the air flow is indicated by the arrows 90 and 92, the transfer of air at the bottom by the arrow 9| and the reverse transfer at the top by the arrow 93. The relatively warm air flowing upwardly in the compartment 26 carries various odors from the produce in the refrigerator. This upward circulation is in the path of the drip of water from the inactive refrigerating unit 28 and as the temperature of this unit rises the frost on such unit melts, causing a water drip to the pan M and the air flowing upwardly is brought in intimate contact with the thin film of water on the inactive unit 28. This water absorbs a considerable amount of the odors of the various foods in the refrigerator and as such water flows intothe drip pan 4I it is carried by the waste or drain pipe 42 entirely out of the refrigerator..

As the air in the unrefrigerated compartment 26 becomes warm and thus lighter and flows upwardly, it is able to carry more moisture than the colder air. A certain amount of this moisture is carried over through the upper openings 24 and comes into direct contact with the active refrigerating unit 21. This causes the condensing in the form of frost or moisture on the unit 21 again causinga cooling of the air passing over this unit and continuing the downward flow of chilled air in the direction of the arrow 90. It will thus be seen that due to the intimate contact of the air flow with the chilling refrigerator 5 unit and with the inactive unit,,that a great deal of the odors from the. food products are carried by the water melting from the warming unit to the drip pans and hence out of the refrigerator. However the air in its circulation is .brought into the intimate contact with the water drip from the cooling unit from which the ice or frost is melting. Thus there is always a desirable moisture contact in the air, thus materially restricting the amount of moisture extracted from food products. Hence with my refrigerator I overcome some of the objections to so-called mechanical refrigeration by eliminating the extraction of moisture from such food products and hence their shrinkage.

v A characteristic of my invention also resides in the thermostat control. For instance when the air in the second c mpartment 26 acquires a sufflciently high te erature, this however being below the point a which food products would tend to spoil, the thermostat in such warm compartment is operated and controls the switching of the flow of the refrigerant from for instance the unit 21 to the unit 28, causing this to become active as the refrigerating unit, thereby 30 chilling the air in contact with this unit 28.

Manifestly in the early stages of this unit 28 coming into operation, the air flowing upwardly is brought in intimate contact with such unit and becomes chilled, thison the increase of density first causes a stoppage of the flow of airas indicated by the arrows 90 and 92 and then reverses the flow so that the air flows downwardly in the compartment 26 and upwardly in the compartment 25. The action is then reversed, the warm air passing over the inactive unit 21 causes a melting of the frost on such unit, the forming of a film of water and this water dropping into the pan and then being discharged by the drain pipe of the refrigerator. The air in this movement is thus brought in intimate contact with the water drip and the water in the pan, thus removing odors carried by the air but still maintaining,

tor. As the cycles are'repeated, the thermostats each acting when they become heated to a predetermined degree, to develop the automatic switching of the flow of the refrigerant from one refrigerating unit to the other and therefore no,

personal attention is required to direct or contol theflow of air in the two compartments of the whole refrigerator.

Various changes may be made in the details of the construction without departing from .the spirit or scope of the invention as defined by the appended claims.

I claim:

1. In a refrigerator, the combination of are- 6 frigerator cabinet having a refrigeration space,

a vertical partition separating said space into two refrigeration compartments, said partition having openings adjacent the top and bottom for circulation of air between the compartments, a refrigerating unit inv the upper portion of each compartment, each unit being thus separated by the partition, each unit having a cooling coil, a

vrefrigeratingfluid is operating and a warm current of air flows upwardly in the other compartment, such warm air being adapted to melt ice formed on the inoperative cooling coils.

2. In a refrigerator the combination of a re- 15 frigerator cabinet having a partition forming two compartments with connections at the top and bottom of the partition for transfer of air, each compartment having means to contain Produce to berefrigerated and each compartment having a go I refrigerating unit in its upper portion, each refrigerating unit being adapted to collect a coating of frost or ice, a. water collecting means positioned to collect the water dripping by gravity from the melting frost or ice on each refrigerator unit, 25 means-to operate a first refrigerator unit and maintain the second unit inactive whereby the air in the first compartment becomes refrigerated and develops a downward flow, the air in the second compartment being adapted to become heat- 30 ed and develop an upward flow, there being a transfer of cold air fr om the first to the second compartment at the bottom and a transfer of warmer air from the second to the first compartment at the top; the said refrigerating units 35 being positioned in the path of the flow of air and the water drip collecting means being positioned whereby the water from the melting frost or ice of a refrigerating unit is brought into intimate contact with thefiowing air, the upwardly 0 flowing air in the second compartment bein adapted to melt the frost or ice from the second refrigerating unit, the first refrigerating unit being adapted to condense and to freeze moisture I from the air .transferred at the topof the partition from the second to the first compartment.

3. In a refrigerator, the combination of a refrigerator structure having a cooling space a separating means forming two cooling compartments in said space, with a connection for interchange of air atthe top and bottom of the separating means, a refrigerating unit inthe upper part of the cooling spaces and on opposite sides of the separating means, the refrigerating units beingadapted to provide an ice surface exposed to air, means to collect the drip 'of water from each refrigerating unit and to discharge such water outside of the refrigerator structure, one of the refrigerating units being adapted to refrigerate the air and to develop a downward flow of air on one side of the separating means, andan upward flow on the other side of the separating means when the second refrigerating unit is idle, the second said refrigerating unit being positioned whereby the upwardly flowing air contacts the ice surface of the second refrigerating unit and melts the ice thereon, the water from the ice dripping into water collecting means, the water collectin means being positioned in the air stream.

" L. O. MONTGOMEBY. 

